A comprehensive computational investigation was performed on the adsorption behaviour of cytarabine anti-cancer drug on the surface of pristine and Fe-decorated (5,5) armchair single-walled carbon nanotube by the density functional theory. The structural parameters, adsorption energies, dipole moments, density of states, the highest occupied molecular orbitals, the lowest unoccupied molecular orbitals, chemical potential, hardness, softness, ΔN, and electrophilicity index of cytarabine and the complexes were analysed. The computed adsorption energies of cytarabine on pristine and Fe-decorated SWCNT are -3.67, and -25.06 kcal/mol, respectively. It means that the adsorption process is exothermic and energetically favourable. Furthermore, quantum theory of atoms in molecules and non-covalent interaction calculations confirmed the existence of weak non-covalent interactions between cytarabine and substrates, supporting the effective drug release. The NBO analysis approved that decoration of Fe atom in SWCNT leads to a stronger interaction with cytarabine than the pristine and so, improves the drug delivery capacity of SWCNT.
